Cain and Abel situation
Attack by the larger of two nestlings on the smaller. The size discrepancy is the result of asynchronous hatching and the 'Cain and Abel' situation is best seen in the Golden Eagle Aquila chrysaetos, which normally produces two young of which the smaller is often killed by the larger. As the obvious expanations, such as lack of sufficient food or innate aggressiveness, do not appear to explain this behaviour, there is much debate as to its cause.From Peter Weaver's Birdwatcher's Dictionary
Copyright © 1981 by Peter Weaver